Rockville, MD (October 17, 2012)–/GlobeNewswire/-Novavax, Inc. (Nasdaq: NVAX) today reported positive top-line results from two Phase 1 clinical trials of its A/H5N1 avian influenza vaccine candidate administered alone or with either one of two undisclosed adjuvants. The trials’ primary objectives of demonstrating the safety and immunogenicity of varying dose-levels of the vaccine with and without adjuvant and the demonstration of statistically significant adjuvant effects on the immune responses were achieved. The vaccine safety was acceptable with no vaccine-related serious adverse events observed.

Stanley C. Erck, President and CEO of Novavax, stated, “The data from these trials represent a landmark event in the history of Novavax. We have demonstrated that Novavax can produce antigens from avian influenza strains that are as, or more, immunogenic than any other described in published results to date. Importantly, as we accelerate our development activities, these results give us tremendous flexibility for pursuing pandemic vaccine products, including vaccines directed at population segments that are sensitive to adjuvant use.”

The two randomized, observer-blind, dose-ranging, placebo-controlled Phase 1 trials were conducted under the company’s contract with the U.S. Department of Health and Human Services’ Biomedical Advanced Research and Development Authority (BARDA). The primary objective of the two trials was to evaluate the safety and immunogenicity of Novavax’s VLP-based H5N1 vaccine candidate at varying dose-levels, with and without an adjuvant, using identical clinical study designs but with a different adjuvant in each study. A total of 666 healthy adults 18 to 49 years old were enrolled in the two trials. Each subject received intramuscular injections of vaccine or placebo at day 0 and day 21, and will be followed for 13 months following the first dose. The current data concern immune responses and safety over the first 42 days.

The adjuvanted vaccines induced strong immunogenicity at all antigen doses tested, including as low as the 3.75 µg dose, based on hemagglutination inhibition assay (HAI) responses against the vaccine virus at day 42.

• 88 to 100% of subjects receiving adjuvanted vaccine at all dose levels demonstrated serum HAI titers =40, a seroprotection level believed to be associated with reduced risk of disease.

• Immune responses would fulfill U.S. Food and Drug Administration (FDA) Center for Biologics Evaluation and Research (CBER) criteria for accelerated approval at the lower bound of the 95% confidence level.

• When tested against another avian A/H5N1 virus different from that in the vaccine, up to 80% of subjects receiving adjuvanted vaccine developed HAI titers =40 against the drifted virus.

Notably, the unadjuvanted vaccine elicited HAI titers = 40 in 83% of subjects at a dose of 45 µg, which would meet CBER criteria for accelerated approval. The unadjuvanted vaccine also elicited HAI titers =40 in 54% of subjects against the drifted virus.

Gregory Glenn, M.D., Novavax’s Senior Vice President and Chief Medical Officer, stated, “We have reviewed the preliminary top-line results of these trials and believe that achieving similar immune responses to our vaccine in future clinical trials, regardless of which of the two adjuvants is used, if any, would meet the immunogenicity criteria for accelerated approval of a pandemic influenza vaccine set by CBER. These data would also fulfill immunogenicity criteria set forth by the European Medicines Agency. The response measured to the drift variant antigen is especially encouraging as the data suggest that our vaccine might be protective when the vaccine strain did not perfectly match a pandemic virus strain, which is an important consideration in the emergent response to a pandemic. We believe we have sufficient data to advance our avian influenza vaccine program into later-stage clinical testing.”

About Novavax

Novavax, Inc. (Nasdaq: NVAX) is a clinical-stage biopharmaceutical company creating novel vaccines to address a broad range of infectious diseases worldwide. Using innovative recombinant protein nanoparticle vaccine technology, as well as new and efficient manufacturing approaches, the company produces vaccine candidates to combat diseases, with the goal of allowing countries to better prepare for and more effectively respond to rapidly spreading infections. Novavax is committed to using its technology platforms to create geographic-specific vaccine solutions and is therefore involved in several international partnerships, including collaborations with Cadila Pharmaceuticals of India, LG Life Sciences of Korea and PATH. Together, these organizations support Novavax’s worldwide commercialization strategy and have the global reach to create real and lasting change in the biopharmaceutical field. Additional information about Novavax is available on the company’s website, www.novavax.com.

Forward-Looking Statements

Statements herein relating to the future of Novavax and its ongoing development of its vaccine products are forward-looking statements. Novavax cautions that these forward-looking statements are subject to numerous risks and uncertainties, which could cause actual results to differ materially from those expressed or implied by such statements. In particular, these statements are subject to the risk that subsequent analyses of trial populations may lead to different (including less favorable) interpretations of the results than the analyses conducted to date or may identify important implications of the study that are not reflected in these statements. Clinical trial data are subject to differing interpretations, and regulatory agencies, medical and scientific experts and others may not share the company’s view of the data or its implications for the company’s pandemic flu program. In addition, later stage studies may fail to replicate the results described in this press release. We can provide no assurance that we will not encounter problems or delays in clinical development of our pandemic flu product candidates or that our pandemic flu product candidates will ever receive regulatory approval or be successfully commercialized. Other risks and uncertainties include those identified under the heading “Risk Factors” in the Novavax Annual Report on Form 10-K for the year ended December 31, 2011, and filed with the Securities and Exchange Commission. We caution investors not to place considerable reliance on the forward-looking statements contained in this press release. You are encouraged to read our filings with the SEC, available at www.sec.gov, for a discussion of these and other risks and uncertainties. The forward-looking statements in this press release speak only as of the date of this document, and we undertake no obligation to update or revise any of the statements. Our business is subject to substantial risks and uncertainties, including those referenced above. Investors, potential investors, and others should give careful consideration to these risks and uncertainties.